IQRP v1.1+ now features a 1Gbps memory cache.This performance
level could be achieved with only a 32/64-bit single core
P4/Athlon CPU! You can limit the maximum cache object size
and the total capacity. When the cache is full, space is
opened by deleting according to the algorithm you select
(i. e. keep most recent, keep most requested...). Cache
contents can be viewed using the remote GUI and emptied.

http://www.fastream.com/iqreverseproxyfeatures.php